The affect of music on learning has been widely researched and there is a lot of variation in performance based on the type of music and the setting where it is used.
There can be no two answers on the question whether loud music hampers study. Loud music only distracts students and diverts their attention from their work. But other research is less conclusive.
In the case of educational programs on television, music has been found to be able to maintain the concentration and attention of listeners and therefore is useful. A preliminary study of the affect of music on students while they are doing homework shows that light music of the students' choice improves performance, though TV shows have been found to be very distracting. In a classroom setting also light music was found to improve performance.
Though inconclusive, the research done till now does suggest a correlation between better performance while light music is being played in the background.